Email used to sign up no longer valid and cannot log in/delete/deactivate blog!

We have a dormant blog that is linked to an old colleague whose email address no longer exists and we cannot log in, nor retrieve the password.
We wish to either DELETE the account completely and set a new one up using the same user name/ URL i.e. username.wordpress.com or get the account changed to another email address, which is very unlikely to happen. We are a company and it is important for us not to have duplicate blogs. Unfortunately, the person who set it up didn't take into account what would happen if he left.

Can anyone help as it's impossible to contact WordPress directly, apparently?
We just need for it to be removed so we can start again, your help is greatly appreciated!